1. Field of the Invention
The present invention relates to processes of coating, consolidating and casting metal particles produced by the Coanda Effect onto a substrate or collector/holder. The apparatus used for effecting the processes is also described.
2. Description of the Prior Art
Composite structures are often prepared in which a coating of special-purpose metallic material is applied to a substrate of a base metal to become an integral structure which possesses desirable surface characteristics. Hard coating for severe wear applications is a typical use which requires application of special surfaces by means other than plating. Techniques presently available are very slow and expensive.
Metallic coating processes other than plating include thermal spray coating, chemical vapor deposition, vacuum coating, sputtering, ion plating, ion implantation, etc. These are described in Volume 5 of the 9th Edition of the Metals Handbook published by the American Society for Metals.
Production of super alloys with superior properties and fineness of micro-structure are produced by a variety of melting, powder metallurgy and consolidation techniques. These include: vacuum induction melting, vacuum arc remelting, powder metallurgy, hot isostatic pressing, extrusion, forging, and the VADER process.
These are typically expensive and complex operations since the severe requirements imposed upon these super alloys require extreme purity and the virtual elimination of inclusions. Many of the most extreme applications are considered to be unachievable by existing powder metallurgy techniques. Recent developments, such as the VADER process, eliminate the powder manufacturing step by the consolidation of semi-liquid droplets (above the solidus temperature, but below the liquidus temperature), which are generated from two consumable electrodes. This is considered to be a likely improvement in production of super alloys required for severe applications. This process is inherently more conserving of energy and capable of producing fine-grained super alloy material which is virtually free of inclusions. The process is, however, a slow one and its cost may preclude its use in all but the most special applications.
There is, therefore, a need for a coating process and apparatus which will produce coatings having special characteristics which are faster and cheaper than those known today. Further, there is a need for a process of producing these special super alloys free of impurities and weaknesses resulting from the prior art processes. There is also a need for a process that will be less expensive and faster than the prior art processes, and also a need for apparatus to effect this process.